Circuit interrupter



Nov. 20, 1951 J. M. WALLACE ET AL 2,575,739

CIRCUIT INTERRUPTER Original Filed June 24, 1941 James M. Cummng and Way/793. Hspy.

;kY/ ATTORN Patented Nov. 20, 1951 UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER Original application June 24, 1941, Serial No. 399,452. Divided and this application March 28, 1947, Serial No. '737,874

I 3 Claims.

This application is a division of' our copending application Serial No. :399,452, filed June 24, 1941, on Circuit Interr-upters and assigned to the same assignee as this invention.

This invention relates in general to electric circuit interrupters and more particularly to automatic reclosing circuit breakers.

Circuit breakers of this type generally include separable contacts, electroresponsivemeans for causing separation of the Contacts, means for automatically -closing the Contacts after a circuit-opening operation, and a means ior automatically maintaining thecontacts separated in response to a predetermined number of closely successivo circuit-opening operations. Circuitbrealers of this type are thus adapted to open the circuit on overloads 'and if the overload is not cleared during the time required for the aforesaid predetermned number of operations, the circuit is maintained open. Iowever, it has been found that these breakers often operate on surge Currents and voltages which, though usually of high values, are of such extremely short duration as to be rendered harmless by lightning arresters connected in the circuit. such Operations of these breakers are undesirable because they lead to unnecessaryoperation of the breakers to the point where the contacts are maintained open to needlessly interrupt service on the circuit.

One object of this inventon, therefore, is to provide a novel automatic reclosing circuit breaker which will not operate on surgessuch -as those caused by lightning.

Another object of this invention is to provide for circuit breakers of the type described having a soienoid coil for causing openingof the breaker contacts, novel means for causing surges tobypass the solenoid coil.

A more specific object of this invention is to provide for an automatic reclosing circuit breaker of the type described, n'ovel means 'for preventing a ci'cuit-openng operation on surgcs comprising a gap in shunt circuit relation with the electroresponsive contact-opening means, which gap is arra-ngeci to break down in response to surges to conduct the surge current around the contact-opening means.

These and other objects of this invention will become more -apparent upon consideration of the following detailed description of a preferred embodiment thereof, when taken in connection with the attached drawing, in which:

' Figura 1 is a substantially central vertical section through 'a circut breaker embodying this Fig. 6 is also a partial sectional View illustrat-.

ing the mechanism of Figs. 4 and 5 in a still diferent position of the parts therecf.

This invention is illustrated as being embodied in a circuit breaker mounted in a tubulainsuating casing 2 which may be of an desired insulating material, preferably porcelan or the like. The casing 2 is provided with a closed bottom and an open top, with the top being closed by a cover assembly 4, and the bottom of 'the casing having associated therewith a terminal assembly 6.

and a, supporting bracket l2 is adapted to be clamped around this cylindrical surface with resili-ent material n interposed between the clamp :2 and the outer casing wall to prevent dama ge thereto. p

The terminal assembly 6 'at the 'bottom of-the casing includes a terminal bolt 14 of conducting material adapted to extend through a substantially central aperture in the bottom casing'wall,

and the bolt is provided with an enlarged head i& interiorly of the casing, with packing material 20 interposed between the head 18 and the bottom wall of the casing. A nut 22 and Washer 24 cooperate with bolt !4 to retain the same' in position, and a conductor 23 may be secured to the bolt, for example, as by a second nut 25.' Bolt :4 is preferably provided with a substan-' tially central bore 38 for the purpose of draining casing 2, the lower end thereof being adapted' to be closed by a screw-threaded closure plug-32.

The upper end of casing 2 is ribbed, and :i supporting anged ring 3 3 is adapted tobe se-- cured to this ribbed portion of 'the casing, for

example, as by cast metal, or the like, 33. *Supporting ring 34 is adapted tohave cover assembly 4 secured thereto in any desired manner, not shown.

The casing andterminal structure 6 describedabove are substantially -identical with thosemore Intermediate the ends of the cas ing 2 there is provided a cylindrical surface a particularly described and -claimed in the abovementioned copending application of H. L. Rawlins and J. M. Wallace, and in their copendin; application, Serial No. 346300, filed July 19, 1940, now Patent No. 2,318,42l, issued May 4, 1943, to the same assignee as this application.

Cover assembly 4 comprises an integral casting having a fiange 38 formed integrally with the lower end thereof and adapted to seat on the upper end wall of casing 2 and extend over the interior of the casing. Flange 38 is also provided with integral outwardly extending ears (not shown) adapted to be bolted to ears formed on supporting ring 34. The cover assembly casting is provided with a hollow portion including the top Wall 40, side walls 42, 43, and end walls 44 and 45, with the bottom of the hollow portion being open and located over the open top of casing 2. At one upper corner of the hollow portion of cover assembly 4, an inclined wall is provided with a threaded aperture for cooperation with a threaded filler plug 46, by means of which casing 2 may be filled with an arc extinguishing fluid. Top wall 40 of the hollow portion of the cover assembly is extended beyond the hollow portion and slightly inclined downwardly as at 48 to form the top wall of a sleet hood portion having side walls 52 and 53. The top wall 48 of the hood portion terminates in an angularly downwardly extending lip 56, for a purpose to be hereinafter described;

As appears from Figs. 1 and 3 of the drawing, fiange 38 of the cover assembly 4 has portions which extend over the open top of casing 2, and these portions are adapted to insulatingly support the circuit breaker contacts and Operating mechanism, for example, as by the tubular insulating spacer sleeves 54. The spacer sleeves 54 have the opposite ends thereof threaded for cooperation with screws 56 and 58, to secure the spacers to fiange 88 and the upper leg !86 of a U-shaped supporting frame 60, respectively. The other leg [88 of U-shaped frame 69 is secured to one end of a generally rectangular frame 64, and the other end of this frame is preferably formed integral with the top cap 6 of an interrupter chamber 68.

The interrupter chamber 68 includes an insulating tube 70 of fiber or the like, having one end threaded into top cap 66, and having the other end threadedly received in a bottom terminal cap 14. Top cap 66 is provided with a substantially central aperture 69 for closely slidably receiving a contact piston rod '12, and the cap is also provided With spaced outlet apertures '13 adapted to be controlled by a sliding valve plate !02, normally biased by coil compression spring !04 into engagement with the adjacent end of insulating tube 10. The lower end cap 14 of the interrupter chamber is provided with inlet passages 16, and with a substantially centrally located threaded aperture for receiving the threaded end of an adjustable fixed contact 18 which is Secured in position, for example, as by a lock nut 86. The outer end of end cap 'Nis reduced in size to form a shoulder 82 on whic is seated one end of a coil compression spring 84 with the other end of this spring hearing against the head l8 of terminal bolt !4. Spring 84 should be of some good resilient conducting material, such, for example, as a copper alloy or the like.

The lower end of contact piston rod 12 is provided with a socket for receiving the upper end t o t t od 8 Sec re ?ethe c t f ex:

4 ample, as by a rivet 88. The lower end of contact rod 86 is enlarged to form a contact head 90. A liquid directing piston 92 is provided with a central aperture 9! so that the piston may be slidably mounted on contact rod 86 for movement between contact head and the lower end of contact piston rod 12. The lower end of contact piston rod 12 is counterbored to receive a coil compression spring 93 which normally operates to bias liquid directing piston 92 to- Wards contact head 90. As shown, piston 92 is provided centrally with a hollow portion to which access is obtained by means of a plurality of top apertures 94, and a single lower aperture 95 concentric with contact head 90 so as to form an annular liquid passage therewith. Liquid director piston 92 may have a periphera slot for the reception of a piston ring 96 to prevent leakage of liquid between the piston and inner wall of tube 19. A stop ring 98 is secured in position between the lower end of insulating tube '79 and lower end cap 14 and, as shown, projects inwardly so as to form a stop for liquid director piston 92, so that when the contacts are closed, the piston is maintained in a position intermediate the limits of its movement on contact rod 86. The inlet apertures 76 in cap '14 are adapted to be controlled by a check valve plate me freely mounted between the end Wall of end cap 14 and stop ring 98. The interrupter chamber 68 described above is substantially identical rhe operation of the interrupter chamber,

herein dsclosed and illustrated, is substantaily the same as that in the above-identified copending application and comprises briefy utinzation of fluid pressures generated by an arc drawn, to obtain contact separation. This is accomplished by the instant structure because it will be observed that as soon as contact piston rod '12 is moved upwardly and contact head 96 moves out of engagement With fixed contact 78 to strike an arc, the action of such an arc on the arc extinguishing liquid within the chamber, such, for example, as oil or the like, will decompose the same to generate a gas which will build up a pressure within chamber 68. As soon as this pressure builds up, it will obviously force check valve plate 189 and valve plate !92 outwardly relative to insulating tube 18 to close both the inlet and outlet apertures 16 and ?3, respectively. Outward movement of valve plate !92 readily occurs because the upper side of this plate is vented by aperture !63. Accordingly, such pressures within the chamber will act on contact piston rod '12 in a piston-like manner to force the same to move outwardly of the chamber, and thereby increase the contact separation. In the upward movement of contact rod 86, liquid director piston 92 remains stationary until contact head 98 engages the upper wall of the director to thereby draw the arc out to an optimum length before moving the director to cause a ow of liquid through apertures 94 and 95 into the arc to extinguish the same. Contact piston rod 12 and contact rod 86 will be moved outwardly by the pressure developed within arc chamber 68 until the combined action of atexample, asby screws 62, or the like.

tehuatonof the are and flow of "liquid therethroughcause extinction. Assoon as the arc isextinguished, the contact piston rod 'Z'S adapted to be moved downwardiy towards fixed contact 18 -in a manner to be hereinafter further described, and since pressure isno'longer being generated within the chamber; spring mawillbe free' to'movevalve plate !632 downwardiy to open -outletpassages-"s and permit exhaust of gases'and used liqud out of the upper end This up-fioW of gas and ofthe arc chamber. used liquid from the'chamber will be taken care of by an in-flow'of fresh liquicl throughinlet apertures 16 which will cause 'check valve piate lflfl to 'be unseated due to the pressure at the bottom of the casing because of the head of liq'uid'therein, and especially because of the diiference in pressure due' to the difference in the head of lquid between inlet apertures ?6 and outlet' apertures consequently, it can be'seen that the fluid pressure developed by the' arc is utiiized in this interrupter to obtain contact' separation, and that during a closing operation of the breaker Contacts, the used arc extinguishing fluid' within the chamber is replaced `by fresh fluid from casingZ.

As' previously stated, the substantially U- shaped'supporting frame member 69 is Secured to" the upper end of rectangular supporting frame 64; and the rame member Gfiis'for the purpose of'supporting 'a solenoid coil'i !2: The upperand lower legs me and !08 of supporting member Ware connectedby^spaced`integral` legs Hil positioned at one side thereof, s'o that the'solenod coi1 ll2 may beassembied with support 60 by merely'slipping the entire `coi1`between iegs lfl'and 'Hit through the open side'of support 63; Thelegs !06 and lsof the' U-shaped frame 60 'are pr ovided with' aligned apertures adapted t'ovcoincide with the central bore provided in solenoid coil HE, and a securing sleeve li of insulatingmaterial, is adapted to be inserted through the aperturein'leg 38' of'theU-shaped support 60 into engagement' with a shouidered plug! e seated against a shoulder provided about the aperture through'leg me of U-'shaped supporting frarne 55. Securing sleeve il is maintained against rr'overnent' downwardly from the supporting frame sa' as Viewed in Fig. 1', by the connection of rectangular' rame' 84 thereto, inasmuch a's the end plate na of this :frame is provided' with a shouldered' aperture, with ,the adjacent end of securing sleeve li seated on thesh'ouider of this aperture to prevent movement thereof with respect to U-shaped frame (iii.` Frame 85 is of magnetic material to form a stationary frame for coilHZ as well as a support therefor. Rectangular frame B t is secured tothe-lower leg D8-of U-shaped frarne Bikfor It will be noted 'that solenoid coil. l l2 is-provided with ai plurality of taps lltwhich are connected to diffrentsections of the coil, and located away frmthe connectirig legs HE of the U-shaped support 66, at the openside thereof so as to be readily accessible for the purpose of changing the coil connections when' desired. Rectangular supporting frame 54 is provided'with the side plat'es l) integral with top plate l !8 at one end thereof, and with top cap 66 for the interrupter chambertat the other end thereof.

Theupper end of contact pisten rod. ?2 is peripherally grooved'asat lzz to form a notch and a iatch projectiori iz at the `upper end thereof,

forco'operation* with a" latcii lever* l 2 6:' The' latch' lever is ada'pted to be 'pivotally mounted ontop* end cap 66- of the interrupter chamber, for example, as byapivot pin [28," and a coil spring" i'is wound about pivot pin !28 with the ends thereof engaging end cap %and latch lever !26,

respectively, for biasing the latch lever in a'` clockwisedirection about its pivot, as viewed in- Fig: 1.- The latch lever is provided with a pluralityof latch lugs i32- and !34 for cooperation with the latch projection !24 on the upper end of contact piston rod and with the core of sole'- noid coii 112; A- contact Operating rod !36' is rigidly securedto contact piston rod 12 andextends from the upper end thereof through a sleeve !31' extending through the central opening ofsolenoid coil H' and securing'sleeve IM. Thelower-end of'sieeve 13? is enlarged as shown at" i33 to 'receive the upperend of a coil compres-` sion spring M with the lower end thereof bearing against the bottomwail of a tubular solenoid coremenber Hi).- The tubuiar solenoid core !40, whichisofmagnetic material, has the bottom wall thereof apertured to be slidably mounted on contact Operating rod [35, andhas adjacent' theupper end thereof a'peripheral inwardly extending rib 142 of'a sizeto closely engage the outer surface of enlarged portion !38 of sleeve 131: Adjacent the lower end of solenoid core MO 'are radiaily' directed vent apertures l for a pur pose to `be hereinafter described.

liti the operation of the mechanism thus -far described, it will be apparent that upon the occurrence of predeterinined circuit conditions, solenoid coil i i'will become sufficiently energized to attract core t& and cause it to move upwardly onoperating rod se and compress spring !M between the core and sleeve 13'?. Furthermore, because of the close fit between core !46, securing sleeve i i i and eniarged portion 538 of sleeve 131 andsince these parts are all immersed in the arc extinguishing fluid, it will be obvious that upward movement of core &se will be relatively slow' because of the necessity of displacing the fiuid within securing sleeve l i i through the relatively smaii clearance between the core and sleeve. However, after sucient movement of the core upwardly so'that rib !42 clears the upper end of enlarged sleeve portion :33, there will then be a relatively large annular'passage through core and' outlet apertures hit for liquid entrapped` in securing sleeve i so that further movement of core i i@ upwardiy will take place at a relatively rapid rate. During this rapid movement of the core, the bottom wall thereof wil engage the iowe'end of enlarged sleeve portion 533 to' cause movement of the sleeve upwa'dly with the' core, and engagement of the upper end of the sleeve with shoulder i 's' formed on contact operating rod !35, will thus quickly separate contact head from fixed contact JS, This movement' of contact head %ii by solenoid core M away from fixed contact ?8 need be but a small amount,

because as soon as the Contacts are separated awar permitted to move downwardly to reclose the contacts. However, its downward motion is halted by engagement of latch projection !24 at the top of contact piston rod 12 with upper latch lug !32. In the meantime, solenoid core !40 returns very slowly under the biasing forces of gravity and spring !44, to the position shown in Fig. 1 because of the dashpot action thereof in securing sleeve !4, so that considerable time must elapse until the solenoid core !48 moves down into engagement with the upper end of latch lever !26, and thereby cause counterclockwise rotation of the latch lever to disengage its upper lug !32 from contact piston rod projection !24. This permits the projection !24 to drop down slightly with contact Operating rod !36, and into engagement with the lower lug !34 on latch lever !26, where it is held until further downward movement of solenoid core !40 causes further counterclockwise movement of the latch lever until projection !24 is released from lug !34, whereupon the contact head 90 is permitted to move into engagement with fixed contact 18. Incidentally, it will be noted that upper lug !32 of latch lever !26 serves as the support for preventing undue downward movement of solenoid core !40. i

The reason why a plurality of lugs !82, !34 are provided on the latch lever to successively halt downward movement of contact head 90 towards fixed contact 18, is that it is necessary to maintain the contacts separatsd during the time delay period before reclosure, a sufiicient distance apart so that the dielectric therebetween will be capable oi safely withstanding circuit voltage. Because of contamination and deterioration of the dielectric on the interruption of high current arcs, this distance is quite large. On the other hand, it is desired to make the time delay between a circuit interrupting operation and a reclosure of the circuit as long as possible with the available time delay means including the dashpot comprising solenoid core !40 and securing sleeve i !4. Lug 582 on the latch lever, therefore, is positioned to engage the moving contact to hold it separated from fixed contact 18 a distance correspondingto the safe gap therebetween according to the dielectric being used. If lug !34 were not also provided on the latch lever, then the time delay between a circuit interrupting operation and a reclosure of the breaker contacts would be too short, and accordingly, to lengthen this period, the second lug !34 is provided for momentarily delaying r-eclosure of the breaker contacts after release of the moving conta ct from lug !32, to thereby obtain a longer time delay in reolosing without undue danger of flashover, inasmuch as the period of time which lug !34 operates to maintain the breaker contacts separated is so short that ionization of the path between the breaker contacts does not have time to be completed prior to reclosure of the contacts. Also on interruption of low currents, the pressure may be insufficient to move contact projection !24 as high as latch lug !32 and since the dielectric will not be unduly impaired by low current interruptions, engagement with latch lug !34 will provide a safe gap between the contacts while using full time delay on reclosure. This feature of the invention together with the special construction of are chamber 68 are disclosed and claimed in application Serial No. 562,'798, filed November 10, 1944, now Patent No. 2,442A77, which is a division of the same application of which'this application is a division.

The upper end of contact operating rod !36 is pivotally secured as by pivot pin to one end of a pair of insulating links !48, with the other ends of the links being connected to an angled crank lever !52, for example, as by the pivot pin !53. crank lever !52 is pivotally mounted at its other end on a shaft !54 extending across the hollow portion of the top cover casting, and its outer ends are mounted in apertures provided in the side walls 42 and 43 of the cover hollow portion, with the outer ends of these apertures being I closed by screw plugs !56 to prevent relative endwise movement of shaft !54. Angled crank lever assembly in a hearing sleeve !12, by a bolt !10,

which also acts to secure an Operating handle !14 to the other squared end of shaft !68. Operating handle !14 is provided at the outer end thereof with a hook eye aperture !16 for the reception` of a hook stick or other Operating member. Actuating handle !14 is limited in its movement in a counterclockwise direction by a stop screw !18 which may be secured in an adjusted position, for example, as by a lock nut !88.

A pair of concentric coil springs !82 and !84 is provided about shaft !54 within the hollow portion of the cover assembly 4, with one end !86 of the outer large diameter coil spring !84 engaging flange 38 of the cover assembly, and the other end !88 thereof engaging the connecting portion !89 of yoke !58, to thereby bias the yoke for movement about shaft !54 in a counterclockwise direction. This movement of the yoke is normally prevented by virtue of the toggle formed by links and !66 being below their dead-center position when actuating handle !14 is in engagement with stop screw !18. One end !90 of the smaller diameter inner coil spring !82 is extended to engage the angled portion of crank lever !52, and the other end of this spring also engages the connecting portion !89 of yoke !58, so that when the yoke is locked by toggle levers !60 and !66 against movement in a counterclockwise direction, biasing spring !82 will operate to bias crank lever !52 downwardly or in a clockwise direction relative to shaft !54, to thereby bias contact actuating rod !36 and contact head 90 downwardly, and cause engagement of the contact head with fixed contact 18.

The circuit through the interrupter herein disclosed extends from a terminal bracket !94 secured to the top cover assembly, for example, as by a screw !98 with the bracket having a terminal socket !86 for the reception of a line conductor, through the cover casting, by way of a conductor 200 to 'one tap !!9 of solenoid coil !!2, through the coil, conductor 202 to contact piston rod 12, contact rod 86, contact head 90, fixed contact 18, end cap 14, compression spring 84, terminal bolt !4, to another line conductor 28. Thus, it can be seen that the solenoid coil !2 is connected in series in the circuit including the breaker contacts, and as shown, the whole coil is connected in series, inasmuch as the end taps of the coil are used, and, therefore, the connection is for the lowest rating of the breaker which can be obtained with the coil employed, inasmuch as the v 9 ::maximumfluxzgenerating -capacityof the/coil, is aemployed.: to thereby :obtain sufficient force ;to

;separate i the 'contactsxon relatively 'low Currents.

;To obtain' higher' current ratings, it would be :merely necessary to'connect conductor 202 or 200 to'other taps H?? of the coil to utilize smaller por- '.tions. ofthe .coil winding. Itwill be notedthat ;the entire circuit'breaker mechanism including ?the breakercontacts and interrupting chamber -are supported; as aunit with the casing cover -assen`b1y`4so thatthey. maybe removed with thetcover from the casing when desired by merely unfastening the securing means of the `cover to support 34 on thecasing. 'Another feature of "the particular supporting :means for the circuit ..br.eakermechanism.-.illustrated, is the specific support of the solenoid coil permitting ready replacement thereofsby. another similarcoil, or by ta, .coil having a: -difiererot :number of turns *to .thereby change the ;available ratings of the breaker. In order to removeooil- !l2,it is mere- :ly necessary toremove screws"52 holding U- :shaped frame 532 andrectangular;frame 64 together. Thispermits securing sleeve I! to drop ..downwardly out of U-shaped fraine' jll,` and then by removing one pivot-ping-ior example; the pivot pin !53, theentire, contact `Operating rod and sleeve !2:7 can be slippedoutof U-shaped frame elisthrough aperturesin legs !05 and !08 cfthe framawhereuponcoill I 2 may be slipped laterally. out of the open sideofU-shaped frame 60. .Toinsert a'new coil, it is'simply necessary to slide it in the openside-of U-shaped frame 60 .until the bore therethrough is aligned with the apertures in legs me and "108 of the frame, where- .upon contact actuating rod !36 and securing sleeve i i may be inserted through the apertures and through the bore in the coil, and rectangular iframe %dsecured tothe *lower leg !88 of the U-shaped supportingframe to thereby rmly secure the solenoid coil in operative position. Consequently, in order to remove the coil, it is only necessary to remove two screws 62, and one pivot pin !59. This feature of the invention is disclosed and claimed application Serial No. i '561,384, filed November 1, lfi lgnow Patent No.

2,468,852, which is a divisionof the same application of which this application is a division.

.Theoperationof` contact biasing spring !82 mounted on shait !54 in cover assernbly is -believed to be obvious from the foregoing. In other Words,-when the circuits interrupted by energization oi" solenoidv coil |l2 suieiently to raise core ldi!` and separatethe 'Contacts against the 'biasvof spring !32,this spring will be effective as "soon as the circuit isinterruptedtomove the contact operating 'od and contact head 90 downwardly towardsfixed 'contact lil, until projection !24 on contact piston rod H is engaged by latch lug !32,` whereupon reclosure oi the :oontacts will be delayed until the latch is released by solenoid core idi] inthe manner.previouslydescribed.

In event an overload oocurs on the circuit 'which iscnot. self clearing but .continues after a 'p'edetermined number of isuccessive interrupting Operations, there .isprovided means for tripping `the toggle whichnormally prevents rotation of `yoke !58, so that spring !84. becomes' effective to "rotatevthe yoke in a counterclockwise direction to "the dottedlineposition shown in Fig. 1 and, con,- sequen'tly, raise crank lever !52, by engagement *of theoross bar !39 ,of the yoke with a projection 19! on the lever, together with-contact actuating rod !36 and contacthead sc to a position wherein the contacthead is maintained out of eng'agement with fixed contact 18, because coil spring !82 :will be ineffective to reclose' the contacts. 'The means for tripping the toggle includesi a cylindrical tube'204 threadedly mounted in the upper'leg !05 of U-shaped support 60, and'providedwith an inlet aperture 208 in the bottom Wallthereof controlled by a* ball-check valve 210 topermit flow of liquid into tube ZM, but preventing cut-flow of liquid. A piston member 205 is' sldably mounted'within cylindrical tube-204, andthe 'upper end thereof is provided with a piu-- ra'lity of'spacedrperipheral grooves 214, 2!G, and am, respective'ly, to form a ratchet-like portion on the piston accessible through a 'sideopening 2:2 in eylindrcalsleeve' 204. A pawl guide rod 225" is"also secured;to leg !05 of U'-shaped support' ti) betweencylindrieal' sleeve' 204 and' contact-'Operatingindit& for'guiding a substantially 'u-shapedpawl member 222, having the connecting 'portion' there'of` slotted; as shown at' *2245150 receive the 'contact opc-rating' rod, and with the ends 'of theslot'extending into the legs 'of :the U' shaped pawl but reduced in width, asshown v at 226, tomore closely fit' guide rod 220 Contactactuating rod !35 is adapted to extend through' the ^slot^224 so that the bottom: portion of the pawl'seats'on ange 232 formedon'the upper-'end oi' 'sleeve !31 sliclable on the contact aotuating rod. Guide rod zzll'is formedwithan 'intermediate' shoulder on which a Washer 228 is adapted-to be seated, with 'a` coil compression spring! 2 3!) engaging between' Washer 228 andxthe lower leg of' U-shaned pawl 222 to normally maintain'the pawl in'theposition shown in Fig; 4.

"In' the operation of the'circuit breaker, itwill be observed'that'each time'solenoid core Mods drawn' upwardly' to open the `circuit and engage the lower 'end of enlarged portion !38 'of -sleeve !31 to' move the same 'upwardlygthat it will cause a 'tilting' 0f'paW1222 against the bias of spring '230,so that the' upper'end thereof moves towards piston'286 'and engages one of the grooves in the pawlportion' thereof,'so that continued upward movement will move' the entire piston upwardly and therebyunseat ball-check valve 2!!! 'and cause a predetermin'ed'amount of liquidto be 'drawn in 'the lower 'end of sleeve 204. As soon -as the'bircuit iisinterrupted, and the contact abtuating 'rod and associated parts are moved downwardly bybiasing spring !82 in the manner previously described, impression spring 230'on *guide rod '220 is operative to withdraw the upper leg of pawl 222 from the notch 2 !A in piston 205, so 'thatthe piston remains at the position to which 'it has been moved; while the Contacts are reclosed. Now, if the'fault on the circuit has been removed, piston 206 will gradually sink to 'the position 'shown in Fig. 4 by displacement 'of the liquid* below the piston through the relatively small clearance between the piston and cylindrical sleeve 204, so that eventually it will attain its origmar position shown in Figs. 1 and 4. However, in' the event the fault in the circuit has not cleared upon the 'first reclosure of the breaker Contacts, they will again be opened by solenoid i 12,' and this .time pawl 222 will'engageinotch 2 i 5 in piston 205,

as shown'. in Fig. 5, inasmuch as the piston will not have hadtime to sink to its original position and the piston will be moved upwardly to the position shown in Fig. 6 of the drawing. .As soon as the arc is extingushed, the contacts will ,again berleclosed by biasing spring !82, andif the fault has cleare d, piston 206 will againslowly sink to its original positionias before. However, if the. fault has not, cleared, before piston 206 has an opportunity to' sink much below the posi- 'piston in its uppermost position.

.tion shown in Fig. 6, the contacts will again be opened, and this time pawl 222 will be pivoted into engagement with the lower notch 2l8 in piston 206 and cause the same to be moved upwardly a further amount and into engagement with the knee of the toggle formed by levers 60 and l 66 to move the knee of the toggle overcenter, thereby releasing spring !84 and permitting the same to rotate yoke I 58 and move the toggle --levers and contact Operating rod to the dotted-line position shown in Fig. 1 of the drawing, wherein the breaker contacts are maintained by spring |84 in an open circuit position.

It will be observed that ordinarily actuating lever !14 is maintained entirely within the hood formed integral with top cover assembly 4, but upon tripping of the toggle constituted by levers -l60 and !66. the actuating lever i" will be moved in a clockwise direction about its pivot axis na to project below the hood, and thereby give a readily visible indication of the fact that the breaker contacts are now maintained in an open circuit position. When piston 206 has tripped the toggle, it will be obs rved that since contact Operating rod !36 is maintained in an upper position, pawl 222 will be maintained in en agement with notch 218 on piston 206 to maintain the Accordingly, when it is desired to manually reclose the breaker contacts by movement of Operating lever I'M in a counter-clockwise direction to reset the toggle levers to the position shown in full lines in Fig. 1, it will be observed in the first place, that in the event it is thus attempted to close the circuit while an overload is present, that the breaker is trip-free in that it is free to open against the bias of contact biasing spring !82 irrespective of the position of actuating-ilever I'M. In the second place, it will be noted that since piston 206 has had but a little time to move downwardly from' its outermost position with respect to cylin- .drical sleeve 204, that in the event the breaker is reclosed manually upon an overload in the circuit, 'that on the consequent circuit interruption and movement of the contact Operating rod and associated parts upwardly, pawl 222 will be caused to engage the lower notch 2 |8 of piston 206 to there- 'by move the toggle overcenter and again permit spring 84 to maintain the contacts in an open position.

Thus, it can be seen that the circuit breaker herein disclosed is capable of automatically opening the circuit with an inverse time delay due to the dashpot action of core 140 in securing sleeve I !4, and yet the contacts are separated with a relatively fast action due to the venting of the dashpot formed by core 140 and sleeve !40 adjacent the end of its stroke. This feature is the invention of J. M. Wallace and is more particularly disclosed and claimed in his copending application, Serial No. 399, 153, filed June 2 1,` 1941, now Patent No. 2,333,604, issued November 2, 1943, to the same assignee of this invention. Fo1lowing a circuit interrupting operation, the breaker contacts are automatically reclosed with a time delay also due to the dashpot action of core !40 and sleeve 4, while maintaining substantially to adjacent the end of the timed period a safe gap between the breaker contacts. Also, in response to a predetermined number ofclosely successive circuit interrupting Operations, novel means are provided for maintaining the breaker contacts in an open position, which includes a biasing means normally held inactive by a toggle which is moved overcenter by a piston actuated a predetermined amount upon each interrupting operation. The arc chamber heren disclosed is provided with an outlet Valve which is positive in operation, and the electroresponsive solenoid contact opening means is supported in a manner to render the same readily replaceable, and is provided with a plurality of taps so that the rating of the breaker may be readily changed. The specific arrangement of the contact closing spring andthe spring for maintaining the contact separated is especially important with respect to space considerations and efiiciency of operation.

The means for maintaining the breaker contacts separated including the toggle, its spring and Operating handle, and the piston for actuating the tcggle, together with the particular manner these means cooperate with each other and with other parts of the breaker are claimed in our aforesaid application of which this application is a division.

An operation counter 236 is adapted to be mounted on the end Wall 45 of the hollow portion of cover assembly l and to be located beneath the hood portion thereof so as to be readily visible from the exterior of the breaker while protected from the elements by the hood. This operation counter may be of any well known type provided with an actuating crank lever 236, mounted on an Operating shait extending through the angled portion of wall 25 like shaft 168, and with crank 236 pivotally connected to an Operating link 238, which, in turn, is connected to pawl 222, so as to actuate the counter on each circuit interrupting operation of the breaker. The connecting link 238 is provided with an insulating portion 240 to insulate the counter from pawl 222.

In accordance with this invention there is provided within the hollow portion of cover assembly 4 in a socket 242 provided therefor on top wall 40, a lightning arrester assembly, which may be of any Well known type including electrodes 256 spaced by an insulating plate 258 to form a gap in series with a porous block 260, in the circuit between top wall :l l of the cover and terminal 244 of the assembly. A tubular insulating sleeve 262 is positioned between the assembly and the side wall of socket 262, and insulating disk 210 supports terminal 246, and is secured to the cover assembly l by screws 266, with a scaling gasket 264 therebetween to maintain the arrester assembly in socket 242. A shunt 268 connects terminal 264 and a contact plate 211, and this plate is maintained in contact with block 260 by a spring 212. The arrester terminal 262 is connected by conductor 246 to the top leg !06 of U-shaped frame 60 to thereby form a circuit bypassing solenoid coil !12. This obviously will prevent the solenoid coil from opening the breaker contacts in response to surges inasmuch as the coil will cooperate with the shunt circuit through the arrester assembly to bypass such surge currents around the coil and limit the voltage across the coil insulation, and such surges will be ineffective to cause a circuit interrupting operation of the breaker. Coil 2 may also be insulated at a reasonable level since it will not be subjected to the high voltages accompanying surges such as those due to lightning; as a matter of fact,

it is not desirable to by-pass coil 2 becausethe protection aorded by the circuit breaker is then lost, but this is taken care of in this onstruction by immediate interruption of current flow in the shunt circuit following the occurrence of a surge, by the cooperative action of block 260 and the gap between electrodes 256. The arrester assembly herein disclosed utilizes a single series porous block and gap of the type shown in the plural series block and gap arrester shown in the patent to L. R. Ludwig et al., No. 2,135,085, issued November l, 1938. It will be understood that plural series porous block and gap assemblies may be used with this circuit breaker, if desired.

Also positioned beneath the hood portion of the cover assembly is a tubular sight gauge glass 250, held in position against an integral lug 248 on end wall 45 of the cover assembly, by an apertured threaded plug 249, and an indicating rod 252 is slidably mounted through the apertured plug and tubular sight glass, and is provided with a fioat 254 secured to the lower end thereof within casing 2 so that the level of liquid within casing 2 may be readily determined from the exterior thereof by inspection of the sight glass beneath the hood portion of the cover assembly.

Thus, there is provided in a single unit an automatic reclosing circuit breaker characterized by its. ability to automatically maintain the breaker contacts in an open circuit position in response to faults which continue a predetermined period of time, and by its inverse time current tripping characteristics with predetermined time delay in reclosing of the circuit, togother with means incorporated in the unit to protect the coil insulation and prevent operation of the breaker in response to the occurrence of surges in the circuit. Moreover, the cover assembly for the breaker casing 2 is arranged with a sleet hood portion at one side therecf to conceal an Operating handle which is projected into view upon lock-open operation of the breaker contacts to indicate this condition, and also houses liquid level indicating means, as well as means for indicating the number of breaker Operations.

Having described a preferred embodment of this invention in accordance with the patent statutes, it is desired that it be not limited to the particular embodiment herein disclcsed, inasmuch as it will be obvious, particularly to persons skilled in the art, that many changes and modifications may be made in this particular embodiment without departing from the broad spirit and scope of the invention. Therefore, it is desired that the invention be interpreted as broadly as possible.

We claim as our invention:

1. An automatic reclosing circuit breaker comprising, separable contacts adapted to be serially connected in an alternating current load circuit, electroresponsive means connected in series circuit with said contacts and of a Capacity such that it is unafiected by the passage of normal load currents therethrough but is responsive to overload currents to cause separation of said contacts, said contacts being biased closed to automatically close the circuit in response to a circuit opening operation, a shunt circuit about said electroresponsive means but not around said contacts, said shunt circuit including normally non-conductive gap means adapted to become conductive in response to high voltage surges to bypass -said electroresponsive means and thus relieve said electroresponsive means of such high voltage surges, and means in said shunt circuit for interrupting the flow of current across the gap in response to cessation of such a high voltage surge.

2. An automatic reclosing circuit breaker comprising, separable contacts adapted to be serially connected in a load circuit, electroresponsive means connected in series circuit with said contacts and of a capacity such that it is unafiected by the passage of normal load currents therethrough but is responsive to overload currents to cause separation of said contacts, said contacts being biased closed to automatically close the circuit in response to a circuit opening operation, a shunt circuit about said electroresponsive means but not around said contacts, said shunt circuit including a gap of a length which will break down on abnormally high voltages, and means for extinguishing the arc struck at said gap to render the gap non-conducting after the disappearance of such abnormal voltages.

3. An automatic reclosing circuit breaker comprising, separable contacts adapted to be serially connected in a load circuit, electroresponsive means connected in series circuit with said contacts and of a capacity such that it is unaffected by the passage of normal load currents therethrough but is responsive to overload currents to cause separation of said contacts, said contacts being biased closed to automatically close the circuit in response to a circuit opening operation, means responsive only to a predetermined number of closely successive circuit interrupting Operations for preventing automatic reclosing of said contacts, a shunt circuit about said electroresponsive means but not around said contacts, said shunt circuit including normally non-conductive gap means adapted to become conductive in response to surges to bypass said electroresponsive means and thus prevent a circuit interrupting operation of the breaker on surges, and means in said shunt circuit for interrupting the fiow of current across the gap in response to cessation of such a high voltage surge.

JAMES M. WALLACE. HERBERT L. RAWLINS. JAMES M. CUMMING. WAYNE S. ASPEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATE'S PATEN'I'S Number Name Date 656580 Thomson Aug. 28, 1900 %3,961 Creighton May 30, 1931 2,069,082 Walle Jan. 26, 1937 2,122,'794 Gethchell July 5, 1938 2,135,085 Ludwig et al. Nov. 1, 1938 2,150,584 MacNeill Mar. 14, 1939 2,152,864 Boothe Apr. 4, 1939 2,158,859 Horikoshi May 16, 1939 2,174A76 Pittman et al Sept. 26, 1939 2,174A'77 Pittman et al Sept. 26, 1939 2,333,604 Wallace Nov. 2, 1943 2,405,606 Rawlins et al Aug. 13, 1946 2,4141786 Lincks et al. Jan. 21, 1947 

